End face inspection device and focused image data acquisition method therefor

Abstract

Provided is an end face inspection device capable of inspecting different end face shapes without replacing an adapter for attachment. An end face inspection device includes: an optical system that forms an image of an end face of a test object, which is fixed at a predetermined position, at a position of an image sensor; and a focus detection section that acquires image data, which is output by the image sensor, and determines whether or not the end face is brought into focus in the image data. The focus detection section acquires a plurality of the image data pieces, in which parts of the end face are brought into focus by changing a focal position of the optical system by a predetermined distance at a time, and acquires focused image data by synthesizing the respective parts brought into focus in the plurality of image data pieces.

What is claimed is: 
     
       1. An end face inspection device comprising:
 an optical system that forms an image of an end face of a test object, which is fixed at a predetermined position, at a position of an image sensor; and 
 a focus detection section that acquires image data, which is output by the image sensor, and determines whether or not the end face is brought into focus in the image data, 
 wherein the focus detection section acquires a plurality of the image data pieces, in which parts of the end face are brought into focus by changing a focal position of the optical system by a predetermined distance at a time, and acquires focused image data by synthesizing the respective parts brought into focus in the plurality of image data pieces. 
 
     
     
       2. The end face inspection device according to  claim 1 , wherein the focus detection section further detects whether or not the end face is inclined on the basis of a brightness of the image of the end face by changing a direction of irradiation of illumination light illuminated on the end face, acquires the plurality of the image data pieces in which the parts of the end face are brought into focus by changing the focal position of the optical system by a predetermined distance at a time under a condition of detection of inclination of the end face, and acquires focused image data by synthesizing the respective parts brought into focus in the plurality of image data pieces. 
     
     
       3. The end face inspection device according to  claim 2 ,
 wherein the optical system includes a slit plate that is provided with a slit passing only a part of illumination light from a light source, and a light source axis correction element that changes an angle of travel of the part of the illumination light passing through the slit, 
 wherein the focus detection section changes the direction of irradiation of illumination light illuminated on the end face through the slit plate. 
 
     
     
       4. The end face inspection device according to  claim 3 , wherein the focus detection section selects pixels which are synthesized from the plurality of image data pieces on the basis of an angle of inclination and a direction of inclination of the end face under the condition of detection of inclination of the end face. 
     
     
       5. The end face inspection device according to  claim 4 , wherein the focus detection section detects a direction of inclination of the end face on the basis of the direction of irradiation of illumination light illuminated on the end face in a case where a brightness of the image of the end face is highest. 
     
     
       6. The end face inspection device according to  claim 2 , wherein the focus detection section selects pixels which are synthesized from the plurality of image data pieces on the basis of an angle of inclination and a direction of inclination of the end face under the condition of detection of inclination of the end face. 
     
     
       7. The end face inspection device according to  claim 6 , wherein the focus detection section detects a direction of inclination of the end face on the basis of the direction of irradiation of illumination light illuminated on the end face in a case where a brightness of the image of the end face is highest. 
     
     
       8. A focused image data acquisition method of an end face inspection device including an optical system that forms an image of an end face of a test object, which is fixed at a predetermined position, at a position of an image sensor, the focused image data acquisition method comprising:
 a plural image acquisition step of acquiring a plurality of the image data pieces in which parts of the end face are brought into focus by changing a focal position of the optical system by a predetermined distance at a time; and 
 a focused image data acquisition step of acquiring focused image data by synthesizing the respective parts brought into focus in the plurality of image data pieces. 
 
     
     
       9. The focused image data acquisition method of the end face inspection device according to  claim 8 , further comprising an inclination detection step of detecting whether or not the end face is inclined on the basis of a brightness of the image of the end face by changing a direction of irradiation of illumination light illuminated on the end face,
 wherein in the inclination detection step, the plural image acquisition step is performed under a condition of detection of inclination of the end face. 
 
     
     
       10. The end face inspection device according to  claim 9 ,
 wherein the optical system includes a slit plate that is provided with a slit passing only a part of illumination light from a light source, and a light source axis correction element that changes an angle of travel of the part of the illumination light passing through the slit, 
 wherein the focus detection section changes the direction of irradiation of illumination light illuminated on the end face through the slit plate. 
 
     
     
       11. The end face inspection device according to  claim 10 , further comprising a pixel selection step of selecting pixels which are synthesized from the plurality of image data pieces on the basis of an angle of inclination and a direction of inclination of the end face under the condition of detection of inclination of the end face. 
     
     
       12. The end face inspection device according to  claim 11 , further comprising a direction detection step of detecting a direction of inclination of the end face on the basis of the direction of irradiation of illumination light illuminated on the end face in a case where a brightness of the image of the end face is highest. 
     
     
       13. The end face inspection device according to  claim 9 , further comprising a pixel selection step of selecting pixels which are synthesized from the plurality of image data pieces on the basis of an angle of inclination and a direction of inclination of the end face under the condition of detection of inclination of the end face. 
     
     
       14. The end face inspection device according to  claim 13 , further comprising a direction detection step of detecting a direction of inclination of the end face on the basis of the direction of irradiation of illumination light illuminated on the end face in a case where a brightness of the image of the end face is highest.